Under conditions closely mimicking vaginal fluid, Lactobacillus jensenii strain 62B produces a bacteriocin-like inhibitory substance that targets and eliminates Gardnerella species

Key bacterial vaginosis-associated bacteria influence each other's growth in biofilms in rich media and media simulating vaginal tract secretions

Bacterial vaginosis (BV) is a very common gynaecologic condition affecting women of reproductive age worldwide. BV is characterized by a depletion of lactic acid-producing Lactobacillus species and an increase in strict and facultative anaerobic bacteria that develop a polymicrobial biofilm on the vaginal epithelium. Despite multiple decades of research, the etiology of this infection is still not clear. However, some BV-associated bacteria (BVAB) may play a key role in the development of this infection, namely Gardnerella species, Prevotella bivia, and Fannyhessea vaginae. In this work, we aimed to characterize the growth of these three species in a rich medium and in a medium simulating vaginal tract secretions (mGTS). We first assessed planktonic growth in New York City (NYCIII) medium and mGTS and observed that the three species showed distinct capacities to grow in the two media. Surprisingly, despite the ability of all three species to grow in single-species in NYCIII, in a triple-species consortium P. bivia was not able to increase its concentration after 48 h, as assessed by qPCR. Furthermore, when using the more restrictive mGTS media, G. vaginalis was the only BVAB able to grow in the triple-species consortia. Interestingly, we found that P. bivia growth in NYCIII was influenced by the cell-free supernatant (CFS) of F. vaginae and by the CFS of G. vaginalis in mGTS. This antimicrobial activity appears to happen due to the acidification of the media. Single- and triple-species biofilms were then formed, and the growth of each species was further quantified by qPCR. While G. vaginalis had a high capacity to form biofilms in both media, F. vaginae and P. bivia biofilm growth was favored when cultured in rich media. Differences were also found in the structure of triple-species biofilms formed in both media, as assessed by confocal laser scanning microscopy. In conclusion, while all three species were able to grow in single-species biofilms in rich media, in mGTS the growth of G. vaginalis was essential for incorporation of the other species in the biofilm.

Simulated Media for Mimicking the Human Environment In Vitro

The phrase 'All models are wrong but some are useful' spoken by George Box in 1976 is as relevant today as ever. Modern research relies heavily on models and the use of in vitro models is the cornerstone of developing novel treatments for various infectious diseases. Simple growth media have been, and still are, heavily used when performing research involving biofilms and infectious pathogens. However, using modern technologies, large discrepancies are now being revealed between bacteria grown in simple media versus those grown in more authentic media. These discrepancies can lead to significant differences in bacterial tolerances, growth patterns, biofilm formation abilities, etc. Hence, if the aim is to replicate the in vivo situation in a laboratory setting, the creation of realistic simulated bodily fluids should be prioritised. This paper presents a range of simulated human fluids from various body sites where infections often occur. Bacterial behaviour has been evaluated in all these media and is often compared to a simple growth medium counterpart. In all instances, significant differences are observed which might lead to important discrepancies, particularly in potential treatment efficiency. We hope this may serve as inspiration for any researcher doing in vitro work, attempting to mimic reality.

Dual Mechanisms of Action: Anti-Candida and Anti-Inflammatory Potential of Lactobacillus Fermentation Broth in Treating Vulvovaginal Candidiasis

Vulvovaginal candidiasis (VVC), a condition predominantly caused by Candida albicans, affects millions of women worldwide, prompting the need for alternative treatments due to the side effects and increasing resistance associated with conventional imidazole antifungals. This study investigated VAGINNE®, a novel fermentation broth derived from Lactobacillus species, as a potential VVC treatment. Using a BALB/c mouse model of C. albicans infection, we evaluated VAGINNE®'s effects on vaginal microbiome composition, inflammatory markers, and tissue integrity. Our findings revealed that VAGINNE® treatment enhanced the growth of beneficial Lactobacillus species while suppressing C. albicans proliferation, leading to a more balanced vaginal microbiome. Additionally, VAGINNE® significantly reduced pro-inflammatory cytokines (IL-17A, IL-22, IL-23) in vaginal tissues and systemic inflammatory markers (IL-6, IL-1β) in plasma. Histological analysis showed minimal fungal invasion and preserved vaginal epithelial integrity in VAGINNE®-treated mice compared to untreated controls. These results suggest that VAGINNE® could serve as an effective anti-Candida and anti-inflammatory agent for managing VVC, offering a promising alternative to traditional antifungal treatments. By promoting a healthy vaginal microbiome, reducing inflammation, and maintaining tissue health, this probiotic-based approach presents a novel strategy for addressing VVC, particularly in cases of drug resistance or adverse reactions to standard therapies. This study underscores the potential of microbiome-modulating strategies in managing vaginal infections, paving the way for more targeted and side-effect-free VVC treatments.

Unravelling the vaginal microbiome, impact on health and disease

PURPOSE OF REVIEW

The vaginal microbiome has a fundamental role in supporting optimal vaginal, reproductive, and sexual health. Conversely, dysbiosis of the vaginal microbiome is linked to vaginal symptoms and adverse health outcomes. This review summarizes recent literature concerning the role of the vaginal microbiome in health and disease, with a focus on the most common vaginal dysbiosis, bacterial vaginosis.

RECENT FINDINGS

Molecular studies have expanded our understanding of the composition of the vaginal microbiome. Lactic acid-producing lactobacilli are an important component of host defences against pathogens, whereas a paucity of lactobacilli is associated with adverse sequelae. Bacterial vaginosis is characterized by low levels of lactobacilli and increased levels of nonoptimal anaerobes; however, the exact cause remains unclear. Furthermore, despite decades of research, bacterial vaginosis recurrence rates following standard treatment are unacceptably high. Strategies to improve bacterial vaginosis cure and promote an optimal lactobacilli-dominated vaginal microbiome are being investigated. Importantly, historical and emerging evidence supports the sexual transmission of bacterial vaginosis, which opens exciting opportunities for novel treatments that incorporate partners.

SUMMARY

A mechanistic and deeper understanding of the vaginal microbiome in health and disease is needed to inform ongoing development of therapeutics to improve bacterial vaginosis cure. Partner treatment holds promise for improving bacterial vaginosis cure.

Protective Mechanisms of Vaginal Lactobacilli against Sexually Transmitted Viral Infections

The healthy cervicovaginal microbiota is dominated by various Lactobacillus species, which support a condition of eubiosis. Among their many functions, vaginal lactobacilli contribute to the maintenance of an acidic pH, produce antimicrobial compounds, and modulate the host immune response to protect against vaginal bacterial and fungal infections. Increasing evidence suggests that these beneficial bacteria may also confer protection against sexually transmitted infections (STIs) caused by viruses such as human papillomavirus (HPV), human immunodeficiency virus (HIV) and herpes simplex virus (HSV). Viral STIs pose a substantial public health burden globally, causing a range of infectious diseases with potentially severe consequences. Understanding the molecular mechanisms by which lactobacilli exert their protective effects against viral STIs is paramount for the development of novel preventive and therapeutic strategies. This review aims to provide more recent insights into the intricate interactions between lactobacilli and viral STIs, exploring their impact on the vaginal microenvironment, host immune response, viral infectivity and pathogenesis, and highlighting their potential implications for public health interventions and clinical management strategies.

Evidence of Lactobacillus strains shared between the female urinary and vaginal microbiota

Lactobacillus species are common inhabitants of the 'healthy' female urinary and vaginal communities, often associated with a lack of symptoms in both anatomical sites. Given identification by prior studies of similar bacterial species in both communities, it has been hypothesized that the two microbiotas are in fact connected. Here, we carried out whole-genome sequencing of 49 Lactobacillus strains, including 16 paired urogenital samples from the same participant. These strains represent five different Lactobacillus species: L. crispatus, L. gasseri, L. iners, L. jensenii, and L. paragasseri. Average nucleotide identity (ANI), alignment, single-nucleotide polymorphism (SNP), and CRISPR comparisons between strains from the same participant were performed. We conducted simulations of genome assemblies and ANI comparisons and present a statistical method to distinguish between unrelated, related, and identical strains. We found that 50 % of the paired samples have identical strains, evidence that the urinary and vaginal communities are connected. Additionally, we found evidence of strains sharing a common ancestor. These results establish that microbial sharing between the urinary tract and vagina is not limited to uropathogens. Knowledge that these two anatomical sites can share lactobacilli in females can inform future clinical approaches.

Bacteriocins: potentials and prospects in health and agrifood systems

Bacteriocins are highly diverse, abundant, and heterogeneous antimicrobial peptides that are ribosomally synthesized by bacteria and archaea. Since their discovery about a century ago, there has been a growing interest in bacteriocin research and applications. This is mainly due to their high antimicrobial properties, narrow or broad spectrum of activity, specificity, low cytotoxicity, and stability. Though initially used to improve food quality and safety, bacteriocins are now globally exploited for innovative applications in human, animal, and food systems as sustainable alternatives to antibiotics. Bacteriocins have the potential to beneficially modulate microbiota, providing viable microbiome-based solutions for the treatment, management, and non-invasive bio-diagnosis of infectious and non-infectious diseases. The use of bacteriocins holds great promise in the modulation of food microbiomes, antimicrobial food packaging, bio-sanitizers and antibiofilm, pre/post-harvest biocontrol, functional food, growth promotion, and sustainable aquaculture. This can undoubtedly improve food security, safety, and quality globally. This review highlights the current trends in bacteriocin research, especially the increasing research outputs and funding, which we believe may proportionate the soaring global interest in bacteriocins. The use of cutting-edge technologies, such as bioengineering, can further enhance the exploitation of bacteriocins for innovative applications in human, animal, and food systems.

Draft genomes of Lactobacillus jensenii UMB0908, UMB1545, and UMB5777 from the urinary tract

Lactobacillus jensenii is a member of the female urogenital microbiome. Previous research has identified strains of L. jensenii that are capable of inhibiting or killing uropathogens, including E. coli. Here, we present the draft genomes of three L. jensenii strains collected from urine samples.